Re: Struggling with c functions - Mailing list pgsql-hackers

You actually almost have it right.

You are passing VARDATA(user) to crypt, this is wrong.

You must do something like this:

int ulen = VARSIZE(user)-VARHDRSZ;
char utmp[ulen+]; // This works in newer GCC, cool.
memcpy(utmp,VARDATA(user), len);
utmp[ulen]=0;
crypted=crypt(utmp,salt);

Strings are not gurenteed to be NULL teminated.


Olivier PRENANT wrote:
> 
> Hi all,
> 
> I'm rewriting my OLD crypt (Thanks to Henrique) C_fonction to version 0
> forms :
> 
> I have this C file compiled OK to a shared library:
> 
> /*
> *
> *  Henrique Pantarotto (scanner@cepa.com.br)
> *  Funcao para encriptar senhas (Function to encrypt passwords)
> *  September 1999
> *
> *  PS: Note that all crypted passwords are created with salt "HP" (my name
> *  initials..) You can change that, or if you know C, you can do in a way
> *  that it will pick two random characters (the way it should really be).
> *
> */
> 
> #include <strings.h>
> #include <unistd.h>
> 
> #include <postgres.h>
> 
> text *post_crypt(text *user)
> {
>  text *password;
>  char * crypt();
>  long now=time((long *) 0);
>  int len;
>  char salt[7]="PY", *crypted;
>  /*strcpy(salt,l64a(now));
>    salt[3]='\0'; */
>  crypted=crypt(VARDATA(user),salt);
>  len=strlen(crypted);
>  password= palloc((int32) 13 + VARHDRSZ);
>  VARATT_SIZEP(password)= (int32) VARHDRSZ + 13;
>  memcpy(VARDATA(password),crypted,len);
>  return password;
> }
> 
> text *sql_crypt(text *user,text *salt)
> {
>   text *password;
>   char * crypt(), *crypted;
>   int len;
>   char s[3];
>   strncpy(s,VARDATA(salt),2);
>   s[2]='\0';
>   crypted=crypt(VARDATA(user),s);
>   len=strlen(crypted);
>   password=palloc((int32) 13 + VARHDRSZ);
>   VARATT_SIZEP(password)=(int32) 13 + VARHDRSZ;
>   memcpy(VARDATA(password),crypted,len);
>   return password;
> }
> 
> /*
> Compile using something like this:
> 
> gcc -I/home/postgres/postgresql-6.5.1/src/include -I/home/postgres/postgresql-6.5.1/src/backend -O2 -Wall
-Wmissing-prototypes-fpic -I/home/postgres/postgresql-6.5.1/src/include -c -o encrypt.o encrypt.c
 
> gcc -shared -o encrypt.so encrypt.o
> 
> And last, you create the trigger in PostgreSQL using this:
> 
> create function encrypt(text)
> returns text as '/usr/local/pgsql/lib/encrypt.so' language 'c';
> 
> If everything is okay, you'll probably have: select encrypt('secret') working
> and showing:
> 
> encrypt
> ------------
> HPK1Jt2NX21G.
> (1 row)
> */
> 
> I have defined to SQL function:
> 
> CREATE FUNCTION post_crypt(text) RETURNS text AS 'xxxx/encrypt.so'
> CREATE FUNCTION sql_cypt(text,text) RETURNS text AS 'xxxx/encrypt.so';
> 
> WHY on earth does
> 
> SELECT post_crypt('test'),sql_crypt('test','PY')
> NOT GIVE the same result???
> 
> Please help,
> 
> This is most urgent (My customer can't use this function anymore); it
> worked OK with 7.0.3!!
> 
> Regards,
> --
> Olivier PRENANT                 Tel:    +33-5-61-50-97-00 (Work)
> Quartier d'Harraud Turrou           +33-5-61-50-97-01 (Fax)
> 31190 AUTERIVE                      +33-6-07-63-80-64 (GSM)
> FRANCE                      Email: ohp@pyrenet.fr
> ------------------------------------------------------------------------------
> Make your life a dream, make your dream a reality. (St Exupery)
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